Mobile storage tank



FIG. 1 is a view of the stairway side of a mobile storage tank inaccordance with my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a view of the walk-in manhole side thereof;

FIG. 4 is a front view thereof; and,

FIG. 5 is a rear view thereof.

An ornamental design for a mobile storage tank, as shown and described.